Fluid-controlling mechanism.



7 Y PATENTED 001'. 20, 1903 J. A. TILDEN. n FLUID GONTROLLING MBGHANISM;

- APPLIGATION FILED APR. 13,-1903. N0 MODEL.

W'Znasaasi I flm/fi JmA.TiZden,

iatented. October 20, 19031.

ATENT union.

JAMES A. TILDEN, OF HYDEPA'RK, MASSACHUSETTS, ASSIGNOR TO HERSEYMANUFACTURING COMPANY, OF SOUTH BOSTON, MASSACHUSETTS, A

CORPORATION OF MAINE.

FLUID-CONTROLLING MECHANISM.

s'rncrsroazrroivrormm part of Letters ram No. 742,136; dated batter 2o,19cc.

Application filed April 13, 1903.

T at whom it may concern:

Be it known that I, JAMES A. TILDEN, a citizen of the United States,residing at Hydepark, in the county of Norfolk and State ofMassachusetts, have invented certain new and useful Improvements inFluid-Controlling Mechanisms, of which the following is a specification.

My invention relates to means for control- 0 ling various conditions ofa fluid in a conducting system; and it consists. in the featureshereinafter described and more particularly claimed.

The drawing shows one embodiment of my 1 5 invention applied, in thisparticular instance, to the controlling of the distribution of waterthrough a meter system.

.The numeral designates a main pipe or conduit, preferably of a diametersufficient to properly supply the maximum amount of liquid which may berequired at any time, and 11 a by-pass opening therefrom, which may beof a suitable size to supply the normal quantity of liquid which is tobe drawn from the system. In the main conduit and by-pass maybeincluded, respectively, meters 12 and 13, which are preferably of suchform and size to efficiently measure the flow through them to insureaccuracy of result and to avoid the introduction of undue resistance. Inthe main conduit between the openings of the by-pass is shown the moreessential portion of my improved controlling mechanism. This, asillustrated, comprises 5 a casing 14, inserted in and forming a part ofthe main conduit, in which casing operates the valve 15, conveniently ofthe reciprocating or gate type, from which projects the stem 16. To thevalve-stem is connected actuating means therefor, which may consist of apiston or head 17, operating in a cylinder or chamber 18. The'cylindermay be so secured to the valve-casing as to form a watertight joint andthe valve-stem pass from the easing into the cylinder through anopening,

giving a close but freely-movable fit, the condition being such thatpacking about the valve stem may be omitted. To prevent leakage in thecylinder by the piston, some Serial No. 152,300. (No model.)

suitable packing 1B is preferably applied to the edge thereof. Openingthrough the casing or other portion of the main conduit at one side ofthe valve and through the cylininder at or near one end is acomparatively small pipe or conduit 20, While a pipe or conduit 21 issimilarly situated with respect to the opposite side of the valve andopposite end of the cylinder. The distance between the openings of thesepipes 20 and 21 into the cylinder is preferably such that the movementof the piston between them will completely open or close the valve.

In the connection above described my llIl? proved controlling mechanismmay be used as follows: A fluid-for example, water-being supplied underpressure to the-main conduit, so that it will move therein in thedirection of the arrow, and the valve 15 being closed, it will be seenthat the piston is acted upon by three forces-the pressure of the fluidthrough the pipe 20 upon the under side of the piston, tending to raiseit and open the valve; the pressure through the pipe 21 upon the upperside, tending to lower it and close the valve, and the Weight of themoving parts of the valve, including the piston, also tending to closeit. It is evident that under such conditions of use as may be termednormal, when the by-pass is capable of conveying and the meter 13 ofmeasuring without undue resistance the water allowed to flow through theconduit, the first two of these forces will approximately balance oneanother. parts remains as a definite force, tending to keep the valveclosed, and, within reasonable limits, this may be given-any desiredvalue, conveniently by varying the thickness of the piston, the closingforce being made of such magnitude that the velocity of the currentthrough the by-pass under normal conditions will not produce differencein pressure enough between the opposite sides of the valve to overcomeit. Now suppose some extraordinary demand is made upon the system, as incase of the use of water for irrigation or the extinguishing of fires.The rate of flow will at once increase and the pressure along theTherefore the weight of the moving conduit proportionately fall, andwhen the difference in pressure at the opposite sides of the valve, andtherefore at the opposite sides of the piston, attains a definitemaximum or is greater than the closing force exerted upon the valve thepiston will be forced upward in the cylinder by the excess of pressurethrough the pipe 20 and the valve opened, permitting the flow throughthe main conduit and its measurement by the meter 12 without materialloss of head. After the opening movement of the valve has beeninaugurated it will continue until the difference in pressure betweenthe opposite sides equals the closing force, at which time this balanceof forces holds the valve in position. It is obvious that, within thecapacity of the main conduit, however the rate of flow is augmented afixed maximum difference in pressure between the opposite sides of thevalve will be maintained, and therefore a definite rate of flow throughthe bypass, since any tendency to increase this difference will at onceresult in an increase in area of the valve-opening and an eq ualizationthereof. On the other hand, if the abnormal demand is decreased theweight of the moving parts, overcoming the excess of pressure upon theunder side of the piston, proportionately closes the valve to stillmaintain the definite differential until when the rate of flow issufficiently diminished the valve completely closes and the normalconditions are resumed. Throughout the entire operation the balance offorces is such that this regulation is smoothly effected and withoutchurning of the piston. It should be noted that when the valve is movedfrom its position of full closure it may be acted upon by still anotherconsiderable force tending to resist the movement. This is the frictionof the edges of the valve against the contacting portion of the casing,which will exert a force depending in magnitude upon the differentialfluid-pressure between the opposite faces of the valve, the ratiobetween the exposed portion of the valve and the piston, and the natureand condition of the contacting-surfaces. By making the valve area thelarger a force resisting initial opening is added to the weight of themoving parts, which is advantageous in that it prevents the starting theflow through the meter 12 upon a slight increase in pressure and theresulting dribbling therethrough of fluid in amounts too small to beproperly measured. Nevertheless after the valve is once opened thisforce is substantially removed by thedrop in the pressure, and themechanism becomes equally sensitive to regulating movement in eitherdirection. By making the piston area relatively the larger the effect ofthis frictional resistance may be reduced to any desired extent until itbecomes practically negligible.

Though my invention has been described for convenience in disclosure asapplied primarily to be a use which may be considered as an automaticswitch for directing the flow of water it is evident that it is in nowise limited to such purpose or in connection with any particularliquid, but, on the contrary, is of general utility wherever it may bedesired to automatically secure operation at or maintain a constantdifferential of pressure between portions of a system in which fluid isconducted under pressure.

Having thus described my invention, I claim 1. The combination with amain conduit for conveying fluid under varying pressures, of a by-passconduit opening therefrom, a meter in the system between the openings ofsaid by-pass conduit, a valve in the system between the openings of theby-pass conduit for maintaining its conduit closed under pressuresresulting in fluid flow properly measurable by the meter, and automaticmeans for opening the valve upon a definite variation in the pressureand then maintaining a fixed difference of pressure between the oppositesides of said valve.

2. The combination with a main conduit for conveying fluid under varyingpressures, of a bypass conduit opening therefrom, a meter in the by-passconduit, a valve in the main conduit between the openings of the by-passconduit maintaining the main conduit closed under normal pressures, theeiiect of such pressures upon the closed valve being to cause aresistance to movement, and automatic means for opening the valve upon adefinite increase in the pressure.

The combination with a main conduit,of a by-pass conduit openingtherefrom through which uninterrupted circulation may occur, a meter inthe by-pass conduit operable at all times under flow through the system,a valve normally closing the main conduit between the openings of theby-pass conduit, and automatic means for opening the valve when the flowthrough the by-pass exceeds the amount properly conveyable thereby andthen maintaining a definite rate of flow through said by-pass.

4:- The combination with a main conduit,of a by-pass conduit openingtherefrom through which uninterrupted circulation may occur, a meter inthe by-pass conduit, a valve normally closing the main conduit betweenthe openings of the bypass conduit, a head connected with the valve, achamber in which the head operates, and conduits leading from thechamber to the main conduit at each side of the valve.

5. The combination with a conduit system for conveying fluid underpressure,of a meter, a gate-valve normally closed during the flow offluid through the system, means for supplying fluid to both sides of theclosed valve, actuating mechanism for the valve, and conduits leadingfrom the actuating mechanism to the main conduit at each side of thevalve.

6. The combination with a main conduit, of

' a by-pass conduit opening therefrom, a meter in the system between theopenings of said by-pass conduit, a valve operating in the systembetween the openings of the by-pass conduit and provided with a stem, apiston carried by the valve-stem, a cylinder cooperating with thepiston, and pipes connecting the cylinder and conduit at each side ofthe valve.

7. The combination with a main conduit,of a by-pass opening therefrom, ameter of suitable capacity in the by-pass through which uninterruptedflow may occur, a valve in the conduit situated at all times between theopenings of the by-pass, actuating mechanism connected with the valve,and conduits leading from the actuating mechanism to the .main conduitat each side of the valve.

' 8. The combination with a main conduit,of"

April, 1903. I

JAMES A. TILDEN. Witnesses:

FRANCIS O. HERSEY, J r., FRANCIS O. HERSEY.

